And would the lap that they're on for a rolling start count?
All laps would count just as they do now.
Process is already in the sporting regulations.
To flesh out an example of how it would work now within the current rules
Red Flag thrown on lap 50
Leader would enter the pits at the end of lap 50
Race suspended at lap 50/51 boundary
Track / Conditions made safe
Race resumption time given with 10 mins notice
Optionally, at race director’s discretion lapped cars given additional full course yellow laps to unlap themselves and rejoin formation in pit lane at end of “lap” 50
(Brazil 2023/2024? Piastri and Ricciardo were denied this opportunity which led to some ire)
Pitlane reformed as thus
Safety Car
Then in position order:-
Cars on lead lap (that completed 50 laps upon entry to pit lane)
Cars (previously) 1 lap down
Cars (previously) 2 laps down
etc
Safety car leads cars out onto track for formation lap (Lap 51)
Race director declares rolling or standing start, RS/SS in white with red border shown on trackside light panels and competitors informed through the official timing system
As per any safety car period, at the S2/S3 timing line lights on the safety car go out, Safety car bolts for pit lane, leader becomes pace car with SC delta time in force still
If SS declared, cars then form up on grid in order, start sequence takes place in normal manner and race resumes on lap 52