UHFJim

I think you have this backwards. UHF performs better in urban areas. Better penetration through buildings. NYPD remains on UHF for this reason. VHF is better in wooded, hilly terrain. https://www.buytwowayradios.com/blog/2008/09/uhf_or_vhf_which_is_right_for_you.html

Best way to go. Smart repeater owners slam the jammers by using a PL or DPL for input (do not list the input on myGMRS), and use a different PL/DPL for receive.

I have no complaints with my Comet 712EFC with 50 ' of Times Microwave LMR-400 cable. Mine is mounted on the side of my house and grounded with an 11 ' grounding rod. I can solidly hit GMRS repeaters in two states from my location with 46 watts. SWR varies from 1.1 to 1.4 across the band. Great antenna for the price IMHO.

https://www.theantennafarm.com/catalog/diamond-sx400-4837 I use the Diamond SX-400 (140-512 MHZ). SWR and both forward and reflected power. 5W 20W 200W settings. It is lighted with a 13.8 dc power source as well.

No problem at all. TK-370G is a nice rig. Enjoy. What antenna are you using?

Not a radio cop but if you "do" ham and GMRS in one radio, You are asking for trouble. Good luck with your setup.

The discone has zero gain, a waste of time unless you are monitoring only. The other antennas you listed are ham antennas, they will be inefficient with high SWR on GMRS. I just installed https://www.theantennafarm.com/catalog/comet-ca-712efc-1085. The antenna is very easy to install, tuned for GMRS, 10 feet tall, and weighs 3 lbs. I pounded an 11 foot grounding rod into the ground and used #6 copper ground wire. 50 feet of LMR-400 with N connectors. The results have been fantastic on GMRS. My ham VHF/UHF antenna setup is a Diamond CR-8900A mag mounted in the attic on a metal plate. It works OK for local repeaters but like I said I prefer GMRS over ham. Your proposed mounting and grounding specs look fine. What kind of support pole and wall mounts are you going to use?

POTS stands for Plain Old Telephone Service. At work we had a dedicated POTS line to be used if our fancy internet linked Avaya phone system went down. https://en.wikipedia.org/wiki/Plain_old_telephone_service

I use a Diamond SX-400