Tube rolling with Quicksilver Mono 60s -- from KT77 to KT88? KT 120? etc.

@glowworm -- harsh highs with GL 88? Whoa. I don't need that. Not just to play around.

It also depends on the amp circuit and what input/driver tubes you use.  

Since you know KT77s now and their signature in your amps, I think it's fair consideration, the highs could be a tad more tipped up (in your amps) particularly when compared to EL34s or KT77s. Always a tradeoff. 

My experience with Tube Rolling on my Monoblocks has been carried out by adopting a advice that was offered by a very experiences Tube Roller.
It was to get the Input Valves exchanged and a Type selected that is allowing the Power Amp to deliver a level of performance that is satisfying my personal preferences.

When this was achieved, the Pre Amp in use was seeming to be the next Device in use that was needing a Investigation.
The theory being that the Input Valves may benefit further from a different Pre Amp. 
The follow up investigations with Pre Amps has also produced a Pre Amp exchange, with the result being a Slagle AVC has been removed from the role of being the Systems Pre Amp.

I have been blown away by the impression the
Nelson Pass DIY Pre Amp has made on me, the Korg B1 is a superb 
device at a very 'affordable' cost, even if a Build Service is used to produce it, as I have done.

The Mono's Output Valves have not been Rolled, and there does not feel any immediate need to undertake this investigation. 
It seems hard to consider more can be achieved to the Measures already being perceived.
I am not shut of from from the idea of Rolling Output Tubes,
but there is a level of satisfaction in place at present, that does not feel it needs to be improved upon.

'All in' I invested about £700 in Tubes and Pre Amp, off which a proportion of the outlay will be recoverable if the unselected
Matched Vintage Tubes are resold. 

What ever the Brand of Monoblocks, I can recommend my experience with Investigations undertaken of addressing the Pre Amplification Delivery to the Output Valves, as a Method to produce a overall SQ that will be seen as very beneficial.
How such a approach will then interface with any exchanges of Tubes used at the Output, is at present a unknown, in relation to my experiences.         

Thanks for the suggestion. It seems like you are saying to consider the preamp as an important factor. I agree. 

Second new Tung Sol 7581A. They're my current tube in 2 sets of monoblocs.  I've also heard good things about new TS EL34B.