Looks like your UP 180s are going to be get in the way of up HSTs
Could you be a little more specific?
As with any major timetable alterations, there would need to be minor adjustments here and there to other services, but the vast majority of UP fast HST's along the Berks&Hants are due into Reading at xx:49 and would preceed the xx:38 stopping train from Newbury (which would be in the bay) passing at about xx+34, and don't conflict with the 180's at xx:25 from Wesbury at all as they pass there at about xx:03?
Also, generally, HST's leave Reading for Paddington (non-stop) at xx:32 and xx:44 and my Reading-Maidenhead-Paddington trains leave Reading nicely in between at xx:37, so, again there's no conflict there - they would follow the xx:42 HeathrowExpress from T5 after Airport Junction.