Here's a (perhaps slightly preposterous) 140-seat (25% tolerance) FPTP Wales:
Let's start with the middle bit that's big enough to see:
Powys33 Welshpool 18478 Yes
34 Newtown 14310 Yes
35 Machynlleth 14201 Yes
36 Radnor 17127 Yes
37 Hay-on-Wye 16920 Yes
38 Brecon 18226 Yes
Ceredigion39 Aberystwyth 18963 Yes
40 Tregaron 14607 Yes
41 Cardigan 16862 Yes
Pembrokeshire42 Fishguard 12992 Yes
43 St David's 13478 Yes
44 Haverfordwest 15433 Yes
45 Milford Haven 13787 Yes
46 Pembroke 16957 Yes
47 Tenby 14415 Yes
Then let's embiggen the North:
Wrexham1 Chirk 16963 Yes
2 Maelor 15940 Yes
3 Wrexham East 15526 Yes
4 Wreham West 15157 Yes
5 Gwersyllt 16571 Yes
6 Rhosllanerchrugog 15723 Yes
Flintshire7 Hope 17051 Yes
8 Mold 16176 Yes
9 Buckley 16604 Yes
10 Hawarden 13226 Yes
11 Deeside 18113 Yes
12 Flint 14327 Yes
13 Holywell 17441 Yes
Denbighshire14 Prestatyn 15144 Yes
15 Rhyl 13058 Yes
16 Denbigh 13452 Yes
17 Rhuddlan 15663 Yes
18 Ruthin 16752 Yes
Conwy19 Abergele 14784 Yes
20 Llanrwst 15401 Yes
21 Colwyn Bay 13881 Yes
22 Llandudno 15222 Yes
23 Conwy 14416 Yes
24 Rhos-on-Sea 15156 Yes
Isle of Anglesey25 Holyhead 14312 Yes
26 Llangefni 19154 Yes
27 Beaumaris 15821 Yes
Gwynedd28 Bangor 17983 Yes
29 Pwllheli 13105 Yes
30 Caernarfon 16299 Yes
31 Porthmadog 14487 Yes
32 Meirionnydd 18218 Yes
And then the South:
Carmarthenshire48 St Clears 13355 Yes
49 Carmarthen 15055 Yes
50 Llandeilo 13136 Yes
51 Ammanford 16123 Yes
52 Newcastle Emlyn 13082 Yes
53 Llanelli 16371 Yes
54 Llangennech 13795 Yes
55 Kidwelly 17988 Yes
56 Pembrey 14982 Yes
Swansea57 Mumbles 15531 Yes
58 Gower 17164 Yes
59 Pontardulais 16321 Yes
60 Loughor 14215 Yes
61 Swansea Sketty 18449 Yes
62 Swansea Cockett 15742 Yes
63 Swansea Llansamlet 15933 Yes
64 Swansea Morriston 16004 Yes
65 Swansea Cwmbwrla 18912 Yes
66 Swansea Central 18551 Yes
Neath Port Talbot67 Pontardawe 16391 Yes
68 Vale of Neath 15186 Yes
69 Neath Abbey 15639 Yes
70 Neath Town 13726 Yes
71 Briton Ferry and Glyncorrwg 13679 Yes
72 Port Talbot North 13760 Yes
73 Port Talbot South 14656 Yes
Bridgend74 Maesteg 14644 Yes
75 Llangeinor 14560 Yes
76 Pencoed 16433 Yes
77 Coity 13040 Yes
78 Bridgend 16925 Yes
79 Porthcawl 12870 Yes
80 Pyle 13212 Yes
Vale of Glamorgan92 Cowbridge 14105 Yes
93 Llantwit Major 14072 Yes
94 Barry West 14570 Yes
95 Barry East 13948 Yes
96 Dinas Powys 17966 Yes
97 Penarth 16395 Yes
Rhondda Cynon Taf81 Aberdare West 13442 Yes
82 Aberdare East 15071 Yes
83 Mountain Ash 13433 Yes
84 Pontypridd North 12370 Yes
85 Pontypridd South 15215 Yes
86 Rhondda East 18736 Yes
87 Rhondda North West 17506 Yes
88 Rhondda South West 12919 Yes
89 Llantrisant 16772 Yes
90 Llantwit Fardre 16787 Yes
91 Pontyclun 14702 Yes
Merthyr Tydfil98 Merthyr Tydfil North 12341 Yes
99 Merthyr Tydfil South 13998 Yes
100 Merthyr Tydfil Central 15743 Yes
Caerphilly101 Rhymney 19362 Yes
102 Blackwood 14626 Yes
103 Abercarn 12690 Yes
104 Risca 13316 Yes
105 Gelligaer 18897 Yes
106 Bedwas 15039 Yes
107 Caerphilly West 16136 Yes
108 Caerphilly East 15482 Yes
Blaenau Gwent113 Tredegar 16068 Yes
114 Ebbw Vale 15074 Yes
115 Abertillery 18519 Yes
Torfaen109 Cwmbran West 16544 Yes
110 Cwmbran East 18744 Yes
111 Pontypool 16805 Yes
112 Blaenavon 14060 Yes
Monmouthshire116 Abergavenny 19397 Yes
117 Monmouth 17402 Yes
118 Caldicot 18182 Yes
119 Chepstow 13286 Yes
And zooming right in on the cities:
Newport120 Newport Llanwern 14162 Yes
121 Newport Ringland 16512 Yes
122 Newport St Julian's 16370 Yes
123 Newport Malpas 14762 Yes
124 Newport Tredegar Park 13430 Yes
125 Newport Rogerstone 12466 Yes
126 Newport Stow Hill 13229 Yes
Cardiff127 Cardiff Rumney 13691 Yes
128 Cardiff St Mellon's 17561 Yes
129 Cardiff Llanisien 15787 Yes
130 Cardiff Cyncoed 18574 Yes
131 Cardiff Roath 18609 Yes
132 Cardiff Splott 13498 Yes
133 Cardiff Canton 19011 Yes
134 Cardiff Bay 18195 Yes
135 Cardiff Castle 16943 Yes
136 Cardiff Rhiwbeina 18455 Yes
137 Cardiff Whitchurch 12673 Yes
138 Cardiff St Fagan's 11786 Yes
139 Cardiff Llandaf 16166 Yes
140 Cardiff Ely 16929 Yes
